The present application relates to a secondary battery including a cathode, an anode, and an electrolytic solution.
In recent years, portable electronic devices such as combination cameras (videotape recorder), mobile phones, and notebook personal computers have been widely used, and it is strongly demanded to reduce their size and weight and to achieve their long life. Accordingly, as a power source of the portable electronic devices, a battery, in particular a light-weight secondary batter capable of providing a high energy density has been developed.
Specially, a secondary battery using insertion and extraction of lithium (Li) for charge and discharge reaction (so-called lithium ion secondary battery) is extremely prospective, since such a secondary battery is able to provide a higher energy density compared to a lead battery and a nickel cadmium battery. The lithium ion secondary battery has a cathode, an anode, and an electrolytic solution. The anode has an anode active material layer on an anode current collector.
As an anode active material contained in the anode active material layer, a carbon material such as graphite has been widely used. In recent years, however, as the high performance and the multi functions of the portable electronic devices are developed, further improvement of the battery capacity is demanded. Thus, it has been considered to use silicon, tin or the like instead of the carbon material. Since the theoretical capacity of silicon (4199 mAh/g) and the theoretical capacity of tin (994 mAh/g) are significantly higher than the theoretical capacity of graphite (372 mAh/g), it is prospected that the battery capacity is thereby highly improved.
For a composition of the electrolytic solution used for the lithium secondary batteries, to improve the battery characteristics such as cycle characteristics, techniques using a compound (sulfone compound) having a sulfonyl group (—S(═O)2—) have been proposed. As the sulfone compound, a chain or cyclic compound having —S(═O)2—O—C(═O)— bond (an anhydride of sulfonic acid and carboxylic acid: for example, as described in Japanese Unexamined Patent Application Publication No. 2002-008718), a cyclic compound having —S(═O)2—O—S(═O)2— bond (disulfonic acid anhydride: for example, as described in Japanese Unexamined Patent Application Publication No. 2004-022336), a cyclic compound having —S(═O)2—S—C(═O)— bond (for example, as described in Korean Unexamined Patent Application Publication No. 2002-0041646) and the like have been used.